The invention relates to a data driving circuit and an organic light emitting diode display, and more particularly, to a data driving circuit without digital latches.
Digital data drivers of a conventional active organic light emitting display use a storage register, digital latch as a line buffer to store digital video data in a signal line cycle.
FIGS. 1A and 1B show conventional 6-bit digital data driving scheme 10. In the scheme 10, binary bits of digital video data are loaded sequentially during a horizontal scan cycle. First, through data lines R[5]˜B[0] binary bits of digital video data are written to corresponding first latches 11, all controlled by a sampling signal applied by a shift register SRn. Next, through data lines R[5]˜B[0], binary bits of next digital video data are written to corresponding first latches 21, all controlled by a sampling signal applied by a shift register SRn+1. Then, all bits of digital video data set are stored in the first latches 11 and 21 are written to the second latches 12 and 22 when the line buffer signal “LB” is asserted and transmitted to the digital-to-analog converters DAC-Rn, DAC-Gn, DAC-Bn at the same time.
The bit number of data increases as resolution goes higher, thus increasing the number of storage registers which occupy layout areas and increasing the number of digital-to-analog converters. In the conventional driving circuit layout, the bit number of data increases as resolution goes higher, and the number of storage registers and digital-to-analog converters are increased accordingly, making the layout more difficult, as the horizontal layout area of the digital data driving circuits is limited.